Carbon nanotubes (CNTs) such as single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are known to have valuable qualities as structural and electrical materials with utility in a wide range of fields as diverse as textiles, concrete, polyethylene, synthetic muscles, high tensile strength fibers, and fire protection. CNTs can be fabricated as electrical conductors, electrical insulators, and electrical semiconductors.
An electrical circuit is typically formed on one side of a semiconductor substrate, and CNTs may be formed on one side of the electrical circuit within a furnace or reactor using a process such as a chemical vapor deposition (CVD). A lower surface of the substrate may rest on a supporting base of the furnace, then a CNT catalyst on an upper surface of the substrate is exposed to a reactant gas within the furnace that chemically reacts in the presence of the CNT catalyst to form one or more CNTs.
Conventional formation of CNTs includes the use of batch processing, where a substrate is placed into a cool furnace, a chamber of the furnace and the substrate are brought up to a target temperature, CNTs are grown on the substrate at the target temperature, the furnace chamber and substrate are cooled, the substrate including CNTs is removed from the cool chamber, and another substrate is placed into the chamber, and the CNT formation process may be repeated.
A batch formation process is inefficient and may be costly compared to a continuous formation process. Additionally, the CNT formation process described above forms CNTs on only one side of the substrate and on one side of the electrical circuit.
A method for forming mechanically robust CNT electrical leads on two or more sides of a substrate and/or on two or more sides of an electrical circuit using a continuous manufacturing process would be desirable.